Draft control means



Jan. 9 1940. J. E. WHETSTINE DRAFiI CONTROL MEANS I Filed Feb. s, 1938 I INVENTOR.

JE55E f. WHETJT/NE ATTORNEY.

Patented Jan. 9, 1940 UN TED- STATES "DRAFT- CONTROL MEANS Jesse B. WhetstinQCedar Rapids, Iowa, assignor of one-half toxH. Everett Rosenberg. Cedar Rapids, Iowa Application-February}, 1938, Serial No: 188,490-

2 Claims.

i This invention: relates: to; heating equipment and has particular relation atogmeans. for, control= ling the draft in furnacesand thelike...

It has been found, in furnaces. 3,1'1d,th6 like;

a that substantially automatic: operation may." be

secured byfilling the furnacejwithcoal and;pro-,

viding a blower'for controllingthe draft to: the furnace. This. blowerf'is preferably controlledfby a room. thermostat and, when; the. thermostat calls for. heat, the blower iszenergized'to;drivepair into the ash pit, which air passes up through the fire and out throughthe; stack to speed up the combustion of the coal. When the room thermostat is satisfied; that is when the temperature in the room has reached a predetermined temperature, the thermostat opens a circuit to a blower motor, and the draft through the furnace is cut off. i

I have found that this system is not entirely satisfactory for the reason that natural convection currents carry air through the furnace and up the stack when the blower is not in operation, thus carrying the heat out the stack. It is possible to provide a solenoid or motor controlled stack damper for opening a check opening into the stack, but such devices are rela-- tively expensive. I have discovered that it is possible to utilize the draft ,in the stack itself for controlling the check draft opening, and furthermore that this operating means located in the stack may be employed to substantially close" off f the stack'when there is no draft in the stack to conserve the heat in the furnace.

It is, therefore, a general object of my inven tion to provide a system of controlling the drafts and check drafts in a furnace.

, It is another object of my invention to provide means for controlling the check draft in a furnace in respect to the forced draft created by a blower.

Other and further features of my invention will be more apparent to those skilled in the art upon a consideration of the accompanying drawing and following specifications, wherein is disclosed several exemplary embodiments of the invention, with the understanding, however, that such changes may be made therein. as fall within the scope of the appended claims without departing from. the spirit of the invention.

In said drawing:

Figure 1 is a View in perspective illustrating a Figure 21s a view in'perspective of a preferred embodiment of my invention as it appears in action. The check draft is in the position it occupies when the draft. created, by. the blower is closed off, and v :Figure;3;is=aview-in perspective of the device shownin' Figures 1 and 2 as it appearswhen the blower is in operation or when-there is a draft through thefurnace. I l Referring now-to the drawing:

Thereis here shown a conventional furnace consisting :of'the ashpit. lfl withits'ash door H, the fire pot l2'withthe feeding door [3, the heaterdome M, the stack [6, and the'furnace jacket IT. A conventional blower is illustrated at I 8.

member 2| substantially rectangular in plan and having a curved flange Zia adapted to fit over the rounded outer surface of the stack 5. At one end of the frame 2| I have provided ears Zlb and Zlc, and these cars receive a cross shaft 22 which is rotatably, mounted in the ears. The frame member 2! may be of any suitable material, as for instance a casting of cast iron.

A check draft plate 23 issecured onthe shaft 22 by means of. openings through the flanges 23a and 23b, and'by means of a boss 230. The boss is provided with a setesc'rew 24, by which it is engaged to the crossshaft 22. Astrap of metal, as illustrated at 26, is secured to-the back face of the check draft plate 23, and extends at roughly an angle of 45 degrees with reference to the plate 23, the angle being so chosen that when the plate 23 is in the ,openposition shown in Figure 2, a disc-like damper 21 is located at right angles to the pipe'l6.

The shaft 22-is bent at right angles outside the frame 2 I, as indicated at 22a, and'a counterweight 28 is drilled to be received on the bent leg of the shaft and is secured thereto by means of the set-screw .29. In use the counter-weight is so located'on the shaft 2?. and the shaft so positioned with reference to the assembly consisting of plates 23 and 27, that normally the damper 2'! will be positioned at right angles to the pipe [6 and the draft damper23 opened to permit air to enter directly into the pipe l6. Whenthe blower I8 is energized the draft created in the stack 16 by means of the blower will I blow the damper 21 to the position illustrated in set up in the stack, but the effect of this damthe damper 21 will tend to return to its original position. Of course it may not return entirely to its original position at once, because of the draft per is to close off the furnace to shut down the draft thereto and to'permit the basement air to enter the stack. I preferably provide a set-screw 3| for limiting the movement of the door 23 to its opened position.

The construction of the device is such that it may be used either in the horizontal position shown in full line in Figure 1, in the vertical position illustrated in dotted lines in Figure 1, or in any angle between vertical and horizontal. 'All that is necessary is slght adjustment of the counter-weight 28 and-the arm 22a of the shaft 22.

Although I have described a specific embodiment of my invention, it is apparent that modifications may be made by those skilled in the art. The device may be adapted for use with large boilers and for use with oil or gas burners or for use with any devices in utilizing blowers. It

the strap, and the cross shaft being bent at right angles thereto to afford means for mounting a counterrweight thereon, and a counter-weight mounted on the bent portion of the cross shaft.

2. In a draft regulating means for use in a stack in conjunction with a furnace and a coal blower, a check draft door, a damper plate fixedly attached at an angle thereto, the check draft door arranged for pivotal movement about a laterally extending shaft, and a weighted means for counter-balancing the Weight of the check draft doorand damper plate to hold said damper plate ina closed position, said damper adapted to be opened and the check draft door closed by the pressure of gases Within the furnace when the blower is inoperation, said check draft door further adapted to be partially opened by an excess of draft Within the stack to thereby partially close the damper.

JESSE E. WI-IETSTINE. 

